Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Right...so I have an inspection coming up in a few months and headers I really dont feel like paying a grand, getting the headers taken off, putting stock manifolds on, and then having the headers put back on. Now what?

Okay so heres my question... well first of all I installed my ebay headers on my 2003 325i (which was a pain in the ass) and im going to have to get my O2 sensor ports moved and welded to a different spot for clearance purposes. But why cant you just plug off your post-cat O2 sensor ports and just tie them up somewhere in your engine bay? Why wouldnt that work? The post cat senors would be out of stream and essentially "tricked" too. So far that is what I have done, and im getting a CEL light. I just want to know why that wont work.

Because the O2 sensors read different O2 levels under acceleration and when coasting. If the car doesn't see the appropriate voltage levels after you take your foot off the gas or for the specific amount of gas applied it throws the CEL.

Ok so heres a question for everyone, i have no running o2 sensors on my car w/headers simply becasue i was left with no room to fit them. I am currently looking into fixing the problem by buying extensions. Now every where i read people say that running the car without o2 sensors is a bad thing especially the post sensors suposedly and others say to ignore it. At this point i have no idea what to think, does anyone have a thread or some input?

I have a couple questions for the op and anyone that has an opinion. I have no 02 sensors on my car due to the fact that i have no room, making it that i have to buy each o2 sensor a 90 degree extension in order to fit them in correctly. I also wanted to do the spark plug non-fouler mod but woudnt i be good with the amount of space i have created with the extensions in order to trick the computer? Idk if im anywhere being right on this. Also does anyone know if my check engine light will go away as soon as plug in the o2 sensors or do i have to clear the code some how?

I'm throwing on a set of headers tomorrow, AMK racing headers for 01-05 on my 323. I know the flanges aren't the same, no worries, fabbing a twin 2.25" center pipe to a ZHP muffler

Question is, the AMK units have very very tall secondary O2 bungs. I'm wondering if it will be necessary to use the non foulers. Here's a picture to show you what I mean. One header has the non fouler, the other doesn't. The one that doesn't, notice how tall it is? The O2 element wouldn't be in the exhaust flow.

like all these ebay headers, youŽll get into trouble when mounting them with installed lambda. theyŽll hit the heatshield. i cutted them more then 3cm, so there was only a small thread which can handle the lambda sensor.

Well the headers and exhaust in installed. Sounds awesome. Mid range and top end power is DRASTICALLY improved. It doesn't die out at 5500 like usually, it pulls hard to 6500.

Like I said, the sound is impressive. Very raspy but a clean sound in idle, clean tuned sound on mid load, screams when opened up. Very well worth mod. Here is the custom exhaust with a ZHP muffler, 2.25" piping, H pipe mid way down (old 323 exhaust with resonators deleted on right for comparison):

Although I did relocate the rear O2 bungs and used the spacers, I'm still throwing a code for cat efficiency. Here is the bung setup:

Here's the AMK headers I threw on. I ceramic coated them black before installation:

Sound clip of a short drive inside the car, windows up:

Sound clip at first hot start-up and small rev to 3300rpm. Notice the rasp on no load and beautiful signature low tone rumble in idle:

Hopefully this can help people decide if they want to go the header route and if so, to resonator or not to resonator.

I too installed the defoulers and I still get the SES light. So like the other guy said its hit or miss. The next cost effective way to delete is that resistor mod, although its not a permanet fix, its cheap. I cant seem to find that post anymore, anyone have a link to that o2 resistor mod diy?